An intubating laryngoscope providing ready interchangeability of blades and a magnifiable video display for use in efficiently positioning an endotracheal tube through the vocal cords into the trachea and teaching the procedure.
In the United States approximately 20-22 million patients are operated on in general surgery and gynecology each year. Of these, about half or more require general anaesthesia in which the patient""s breathing functions are temporarily disabled. Ventilation is supplied to the patient by the anesthesiologist during the procedure.
Ventilation is provided through an endotracheal tube. This tube is inserted into the trachea, and it is closed against the wall of the trachea by an inflatable cuff. The insertion of this tube involves risks that the anesthesiologist seeks to avoid or at least minimize. It is estimated that between one in 6,000 to one in 8,000 general anaesthesia procedures result in death. There are of course many causes but of these it is estimated that about one third of them are caused by the intubation procedure.
The principal problems the anesthesiologist encounters are the remoteness of the location where the tube is to go, the consequent restriction of view as the tube is inserted, variations and anomalies in the anatomy of the patients, an uncomfortable and unnatural position for the anesthesiologist, the potential need to change blades, and the necessity for rapid intubation.
It should be remembered that when the tube is to be inserted, the patient is asleep, and when he has been paralyzed for the procedure he is not breathing and the ventilator is not yet in operation. This gives the anesthesiologist only about two minutes in which to intubate the patient, inflate the cuff, and start ventilation. If he is delayed by the need to change blades of conventional instruments or by clumsiness of the instrument, he must stop, apply a mask, supply oxygen for a time through the mask, remove the mask, adjust medication if necessary, and then start over again. This delays the operation and extends the time under anaesthesia. Especially for elderly patients this is a very serious matter.
However, the need for speed cannot be permitted to expose the patient to greater risk. Severe damage can be done to the larynx and vocal cords, for example, by a tube which makes inappropriate contact with them. The object is to pass the tube smoothly where it will do no damage, namely directly between the vocal cords.
The direct visualization of the vocal cords through an open tube, which was the standard instrumentation for many years, gave only a limited and very unsatisfactory view of the region. It was like peering through a small keyhole into a dimly-lit region. Furthermore, it required the anesthesiologist to assume a most inconvenient posture while peering through the instrument, manipulating it with one hand, and pushing and turning the tube with the other. In practice it often required a xe2x80x9cthird handxe2x80x9d to manipulate a stylet which is often used. The literature and conversation in this field often refers to a third hand; (i.e. the need for an assistant).
With the advent of endoscopic equipment and small cameras, instrumentation has been improved to the extent that it can enable viewing of the cords and larynx on a screen. This in itself was a great advance in the field.
However, conventional instrumentation still fails to provide the anesthesiologist with an instrument which as to him is entirely standard and requires no special training, which provides an optimal video display of a full field of view that can be magnified, which can be fully utilized with only two hands without the need for an assistant and without stylets, in which blades can be changed quickly to account for the anatomical structure of the individual patient, and with which training can be done and records and teaching videos made.
It is an object of this invention to provide such an instrument with its stated advantages, especially those of accuracy, familiarity, rapidity, and efficiency.
An instrument according to this invention includes a standard handle for the anesthesiologist to hold, a camera, a plurality of blades each having a configuration appropriate to a specific anatomical configuration, and a separable hinge type joinder having a portion on the handle and on each blade, the handle and the blades together forming a standard configuration familiar to all anesthesiologists trained in this procedure.
According to a feature of this invention, a cable guide tube extends along each said blade from a location adjacent to said joinder to a location near the tip of the blade. A flexible cable extends freely from the handle. It is inserted into the cable guide tube when the blade is attached to the handle. It is correctly positioned where the joinder is closed.
The cable itself conducts light to illuminate the field ahead of the tip of the blade. The cable also includes means to convey an image or data respective to an image of the region. When the camera is in the handle, the means in the cable is a coherent fiber optic bundle. When the camera is placed at the end of the cable, the means is a conductive lead.
In either arrangement, image bearing means and illumination means are carried by the cable respectively to obtain an image of it and to illuminate the region.
The light source may be a conventional battery and light bulb arrangement carried in the handle, or according to a preferred feature of the invention it may be a separate light source connected to the handle by a light-transmitting fiber optic bundle. With the use of this bundle, which may pass over the shoulder or to the side of the anesthesiologist, there is no interference with his movements or with the free advancement of the endotracheal tube.
The video display receives the image signal from the camera through a lead that extends from the handle. When an external light source is used, its fiber optic bundle will also exit from the handle. The lead and the bundle can conveniently exit from the back of the handle, and pass over or beside the shoulder of the anesthesiologist.
The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings, in which: